Purpose: The aim of this study was to develop a child self-report questionnaire measuring bilingual experience and self-perceptions of Spanish and English proficiency and establish preliminary evidence of validity and reliability for the questionnaire. Method: Participants included 113 Spanish-English bilingual children with and without developmental language disorders ranging in age from 4 to 8 years. All children completed the questionnaire in Spanish and participated in behavioral assessment of their language skills in both Spanish and English. Results: Using confirmatory factor analysis, a model with three correlated factors (self-perception of proficiency in Spanish, self-perception of proficiency in English, and bilingual experience) emerged with the best global fit, reasonableness, consistency with theory, and model parsimony, suggesting that the questionnaire has good internal reliability. The scaled results of the questionnaires significantly correlated with behavioral measures of both Spanish and English, supporting the convergent validity of the measure. Conclusions: The Houston Questionnaire is an assessment tool for the assessment of bilingual experience and self-perception of proficiency in Spanish and English bilingual children between the ages of 4 and 8 years. The results provide foundational evidence supporting the reliability and convergent validity of this tool.